Electronic mail, or e-mail, is fast becoming a dominant mode of communication. In its primitive form, e-mail is managed by two kinds of computer software: namely, e-mail server software (referred to simply as “e-mail servers”) and e-mail client software (referred to simply as “e-mail clients”). E-mail servers reside on centrally accessed computers (referred to as “server computers”), and manage incoming and outgoing e-mail for remote users who are authorized to use such server computers. E-mail servers maintain separate mail accounts for each authorized user, into which incoming mail is stored. E-mail clients reside on remote computers (referred to as “client computers”) and manage incoming and outgoing mail for designated users. E-mail clients are responsible for downloading arriving mail items from the server computer at which they are located. E-mail clients are also responsible for transmitting outgoing mail from a remote client computer to a server computer. Examples of popular e-mail clients for personal computers are EUDORA R, INTERNET EXPLORER R and NETSCAPE R.
Standard e-mail uses a protocol named Simple Mail Transport Protocol (SMTP) for sending outgoing messages, and a protocol named Post Office Protocol (POP) for receiving incoming messages. Other techniques and protocols for sending and receiving e-mail may also be used, as appropriate. For example web based e-mail, using the HTTP protocol may be employed.
For use over the Internet, MultiPart Internet Mail Extension (MIME) extends the format of Internet mail to allow non-US-ASCII textual messages, non-textual messages, multipart message bodies and non-US-ASCII information in message headers. Attachments to e-mail messages can be included within a multipart e-mail. One of the drawbacks with e-mail, however, is the need for a user to be connected to the Internet in order to receive or send his e-mail.
Although Internet access is available in many homes and offices, and Internet stations are available in many public areas, being “un-wired” is still a concern for mobile users who are neither at home nor in their office. When on the road, a user often finds himself unable to access his e-mail, for a variety of reasons.